Apparatus for forming cam surfaces upon cylindrical cam bodies



Oct. 8, 1946 A. ANDERSON APPARATUS FOR.FORMING CAM SURFACES UPON CYLINDRICAL CAM BODIES 2 Sheets- -Sheet I Filed April 7, 1945 A m m w.

Oct. s, 1946.

A. ANDERSON APPARATUS FOR FORMING CAM SURFACES UPON CYLINDRICAL CAM BO DIES Filed April 7, 1945 2 Sheets-Sheet 2 I INVENTOR.

BY L "*6 Patented Oct. 8, 1946 UNITEDg STATES PATENT OFFICE I APPARATUS FOR FORMING CAM SURFACES. UPON CYLINDRICAL CAMBODIES Arthur Anderson, Brooklyn, N. Application April 7, 1945, Serial No. 587{,126

. l 1 i My inventionrelates a cam surface upon a cam body of the cylindrical 1 Claim. (cur-101) toapparatus for forming type and, more particularly, to a device adapted to be used as an attachment fora grinder, or the like .metal removing machines, so as to convert the grinder into apparatus especially useful in refinishing worn cams. V I It is an object of the invention to provide a simple device for accurately positioning and feeding acylindrical cam body to a cutting tool for forming a cam surface having a desired degree of rise for a given arcuate length. a It is a further object of the invention to provide apparatus capable of using a given master cam or template for. operating upon a plurality ofcams of different sizes toproduce the same rise per degree of circumference as that of th master cam or. template. I

Itis a furtherobject of the invention to.pro-. ,vide a sturdy, low-cost! device which may .be readily attached to andused in conjunction with a grinding machine, milling cutter, planingrnachine, or the like for forming a cam surface on a cylindrical cam. Y f I It is a further object of the invention to provide adevice for forming cam surfaces upon respective cam bodies of various sizes, both as to diameter, thickness of face and extent of rise.

Other objects, advantage and features of the invention will become apparentfrom the follow- 'ing detailed description taken in conjunction with the appendeddrawings, in which: V Fig. l is a frontelevational view showing my novel device as adapted more especially for operation with a grinding machine; i

Fig. 2 is aside view of the device shown in Fig. l;

Fig, 3 is a top view of the device as shown in Fig. 2 with certain parts of the grinder omitted for clarity; Fig. 4 is a sectional view, taken along the line 4-.-4 of Fig. 2, with certain parts broken away;

and

Fig. 5 is an enlarged sectional view taken alon the line 5 5 of Fig. 3, and showing the grinding wheel which i omitted in Fig- 3.

Referring more particularly to Figs. land 2, I have shown, as one form of a cutting machine, a grinding machine I 0 of conventional form. comprising a frame Illa providing a, journal having a removable cap lob suitably secured thereto as by bolts I00, I00 and serving to rotatably support a shaft ll having a grinding wheel l2 suitably.secured thereto for rotation about its horizontal axis H by any suitable sourceof poweririot shown). The grinding machine It further comprises avertically-adjustable supporting bed. l3 which i suitably secured to the frame 10a and carries a work. table M which is movable'both longitudinally and transversely with respect to the horizontal axis H of grinding wheel l2. As shown bestin Fig. 2, the work table I4 is provided with transversely-extending T slots at; Thus far, I have 'referredto-pertinent feature of a typical well-known surface grinder. 'It'is to be understood, however, that I do not limit myself to the particular type of grinding machine shown as the invention is applicableto various types of grinding machines or evenin its broader aspects, to planing or v milling machine aswill more fully appear hereinafter.

} According to the present preferred form of the invention, a split pillow block l5 comprising, a

lower section Mia and an upper section l5b is rigidly secured to the work table 14 by means of T bolts I50, I50 the heads of which aredisposed withinone of the slotsll la, The upperlsection 15b of the pillow block I5 is clampedto the lower section He by bolts I511, l5d thus defining: a tubular bore in which is rigidly held a cylindrical extension [6a of a supporting base |6. To assure the unitary rigidity of the base l6 and block IS, a flush headset screw ,(not. shown) preierably is screwed upwardly through the lower block section -I5a and into engagement with the cylindrical portion 3a. The base or gbottom flange of the lower pillow blockmember Ilia is provided with alower surface disposed in a plane at right angles to the'aXis .V, and accordingly when the device is .held' in position on a horizontal bed such as H the axis V is vertical. Carried by the-base I6 is a cylindrical stub shaft ll, the axis .V of which is vertical at all times. For convenienceth shaft I! is madeas a separate member snugly seated in a bore in the base l6 and rigidly locked thereto by a screw [61).

A collar IB encircles the cylindrical member l1 and is supported by the base It for removably holdings master cylindrical cam or template IS. The template-His rigidly held on the collar 18 by'screWs'lSa; [9b and one of thesescrewssuch as lBb, extends through the. collar'litand engages the cylindrical member IT to thereby rigidly secure the template to the shaft-11- while permitting ready adjustment of the template angularly. As is apparent from Fig.4, the template 19 has a substantially semi-circular configuration. However, the angular extent ofthe template l9 may vary from a portion .of .a quadrant, to .360

degrees, depending upon the arcuate extent of the cam surface to be formed, without departing from the spirit and scope of the invention. The template I!) has an inclined upper surface S, Fig. 1, the lowest portion thereof being at S1 and the highest portion at S2. For convenience, a horizontal plane P, P passing through S1 may be considered as a reference plane. Those skilled in the art will recognize that the rise at any portion of the upper cam surface S is its vertical distance above the horizontal plane P, P and the Vertical distance of the upper cam surface S from the plane P, P at S2 is the total rise of the cam. Similarly, the rise per degree of circumference of the template i9 is the difference in elevation of two points upon the cam surface S which are separated by an angular distance of one degree.

Rotatably mounted upon the cylindrical member I1 is a work carrier having a horizontallyextending stub-shaft 20a, Fig. 2, upon which is journalled a roller 20?) engaging the upper surface S of template IS. The work carrier 20 is movable axially with respect to the cylindrical member [1, this axial motion being controlled by the height or rise of the upper surface S of the master cam IS. The upper portion 200 of the work carrier 20, Figs. 2 and 4, is circular and has a flange 20d upon which is carried the base 2|a of a cylindrical cam body 2| which is to be provided with the proper contour as determined by the shape of the template IS. The cam 2| is firmly secured to the work carrier 20 in any suitable manner as, for example, by screws 2|b, 2 lb, the center of the cam 2| being disposed upon the axis of rotation of the work carrier 20. While the invention is intended especially for the regrinding of worn cams it is within the contemplation of the invention that it may be used to initiall cut or form a new cam surface in which case the cam body 2| takes the form of a suitable cam blank. The work carrier 20 is provided with a handle 20) by which it may be rotated about the cylindrical member l'l. Thus, as best shown by Fig. 1, it will be apparent that, as the work carrier 20 is rotated, the roller 2% moves along over the upper surface S of the master cam IS with the result that the work carrier 20 moves vertically in accordance with the degree of rise of the upper surface S of cam I 9. In other words, as the work carrier 20 together with the roller 20b is rotated through an angle of one degree, for example, said work carrier 20 moves a vertical distance equal to the rise per degree of circumference of the template Hi. It will be apparent that cams of any desired diameter or thickness or height may be resurfaced or cut by choosing a suitable work carrier 20', the upper portion 200 and flange 20d of which conform to the inner and lower surfaces, respectively, of the cam body 2|.

Operation Referring to Fig. 2, with the parts assembled as previously described, the Work table I4 is moved transversely with respect to the axis H of grinding wheel l2 until the vertical axis V of the cylindrical member H, on which the centers of the template l9 and cam body 2| are disposed, intersects the horizontal axis H of the grinding wheel l2. The work table I4 is then moved longitudinally with respect to the axis H until the grinding wheel I2 is in position to make a cut of the desired width upon the cam body 2|, Fig. 5. Thus, it will be apparent that I prefer to grind away'the Worn or rough surface of the cam body 2| by increments, only a small portion being ground away at each cut. However, under some conditions, the whole width of the upper surface of cam 2| may be ground away at one cut.

The supporting table l3, Fig. 2, is then vertically adjusted to give the desired depth of out which is kept as shallow as possible to conserve the metal of the cam surface. Preferably, the cam 2| is rotated to such a position during this operation that the grinding wheel l2 does not engage the surface of cam 2|.

The grinding wheel I2 is then rotated at a high rate of speed and the work carrier 20 together with the cam 2| are rotated by the handle 20f, for example, in a clockwise direction, Fig. 3. As the highest portion T of the upper surface of cam 2.| comes into engagement with the grinding wheel I 2, the roller 20b is in engagement with a relatively low portion, for example S1, of the upper surface S of template I 9, Fig. 1. As rotation of the work'carrier 20 continues through an angle of one degree, for example, the roller 20b travels along the upper surface S of template l9 whereby the work carrier 20 together with the cam 2| moves vertically upward with respect to the grinding wheel I2 a distance equal to the rise per degree of the template l9. Accordingly, as the cam 2| is rotated, the vertical distance D, Fig. 5, of the newly-ground surface N of cam 2| from the base 2|a thereof decreases in accordance with the rise of template l9. As the cam 2| is rotated through an angle of one degree, for example, the distance D decreases a distance equal to the rise per degree of circumference of the template I9. Rotation of the work carrier 20 is continued until the whole circular length of the upper surface of cam 2| has been ground away, the newly-ground cam surface N thus having the same rise per degree of circtunference as the template l9.

The work table 4 together With the cam 2| are moved to the right, Figs. 2 and 5, and another portion of the cam surface of the cam 2| is ground awayby rotation of the Work carrier 20 together with the cam 2| by the handle 20). This adjustment of the work table I4 and grinding are continued until the whole width of the surface of cam 2| has been ground. In this manner, I obtain. a reground cam surface having the same rise per degree of circumference as the template l9, and th finished surface is accurately horizontal in a radial direction throughout its arcuate length. Also a smooth ground finish is provided, not obtained by any other method, consequently prolonging the life of the cam.

It will be obvious to those skilled in the art that the grinding wheel |2 could be replaced by a milling cutter or a planing tool without departing from the spirit and scope ofthe broader aspects of my invention. Therefore, it is to be understood that the term metal removing tool in the appended claims is descriptive of a grinding wheel, milling cutter, planing tool, and the like. It will further be apparent that while the invention is intended especially for use in refinishing cylindrical cams of the type used in single and multiple automatic screw machines, the surface of th template 9 could be of a different or irregular contour, if it is desired to provide a cam whose active surface is of such different or irregular shape. 7

,While the invention has been described with respect to a presently preferred embodiment which has given satisfactory results, and certain modifications have been referred to, it will be understood by those skilled in the art, after understanding the invention, that various other changes and modifications may be made without departing from the spirit and scope ofthe invention and it is intended, therefore, in the appended claim to cover all such changes and modifications as fall within the scope of the invention. l r

Iclaim:

In apparatus comprising a rotatable grinding Wheel for forming a cam surface wherein a Work table is movable in a direction normal to the axis of said grinding wheel, said Workvtable being adjustable longitudinally and transversely with respect .to said axis, the combination with said apparatus of a detachable fixture including a base rigidly secured to said table and providing a vertically extending cylindrical portion. constructed and arranged for the insertion thereover of a surrounding arcuate template, said base also providing a cylindrical bearing portion having a vertical axis of rotation coincident with 

